[MacPorts] #63818: gromacs/gromacs-plumed: build requires macOS 10.13+; possible candidate for macports-libcxx

[MacPorts]

#63818: gromacs/gromacs-plumed: build requires macOS 10.13+; possible candidate for
macports-libcxx
-----------------------------+------------------------------------
 Reporter:  mascguy          |      Owner:  dstrubbe
     Type:  defect           |     Status:  assigned
 Priority:  Normal           |  Milestone:
Component:  ports            |    Version:  2.7.1
 Keywords:  macports-libcxx  |       Port:  gromacs gromacs-plumed
-----------------------------+------------------------------------
 These ports fail to build on macOS releases earlier than 10.13, with the
 following errors:

 {{{
 src/gromacs/modularsimulator/computeglobalselement.cpp:393:62:
   error: 'value' is unavailable: introduced in macOS 10.13
     return std::any_cast<ISimulatorElement*>(cachedValue.value());
                                                          ^
 /opt/local/libexec/llvm-9.0/bin/../include/c++/v1/optional:944:33:
   note: 'value' has been explicitly marked unavailable here
     constexpr value_type const& value() const&
                                 ^

 src/gromacs/modularsimulator/computeglobalselement.cpp:393:21:
   error: 'any_cast<gmx::ISimulatorElement *>' is unavailable: introduced
 in macOS 10.13
     return std::any_cast<ISimulatorElement*>(cachedValue.value());
                 ^
 /opt/local/libexec/llvm-9.0/bin/../include/c++/v1/any:581:12:
   note: 'any_cast<gmx::ISimulatorElement *>' has been explicitly marked
 unavailable here
     _ValueType any_cast(any const & __v)
                ^
 }}}

 However, the use of `macports-libcxx` might be on option on 10.12 and
 earlier, to fix these issues. @kencu would be able to say for sure,
 though.

 In the interim, we should set `known_fail` as appropriate, to save wasted
 buildbot time.

-- 
Ticket URL: <https://trac.macports.org/ticket/63818>
MacPorts <https://www.macports.org/>
Ports system for macOS